Data processing systems which permit the processing of data in a windowing environment have been known for some years and have made the interaction between users and the system more user-friendly. However, even with the use of windows, the management of all the information that users wish to place on the display screens of data processing systems may not be easy. For example, where a number of tasks are to be performed and there are possibly many overlapping windows on a screen, it is often difficult to arrange related windows in a meaningful way.
One approach to the structuring of data has been described by Henderson and Card in "Rooms: The Use of Multiple Workspaces to Reduce Space Contention in a Window-Based Graphical User Interface" --ACM Transactions on Graphics, Vol. 5, No. 3, July 1986, Pages 211-243. This article describes a system in which a plurality of virtual screens, or "rooms" are defined in each of which different tasks may be performed.
In order to change the room which is displayed this prior system makes use of the concept of a "door". A door is basically a icon which can be selected and causes the workspace to be changed. It will be appreciated that when one wants to change rooms, one might well want to take some of the items being processed from one room to another. The article refers to these items as "baggage". Despite the many advantages of the concept of "rooms", the selection and transfer of baggage from one room to another are rather cumbersome and time consuming processes.
The management of information is a problem particularly in multi-user systems. It has bene proposed to use workstations in a system which permits real time dynamic interaction between a plurality of users on what can be described as a "what you see is what I see" (WYSIWIS) basis. An example of such a system is described by Stefik et. al. in "Beyond the Chalkboard: Computer Support for Collaboration and Problem Solving in Meetings" --Communications of the ACM Vol. 30. No. 1, Jan. 1987, pages 32 to 47.
Stefik et. al. describe a data processing system comprising a plurality of workstations each having a display device. The aim of the system is to support a meeting between a number of users of the workstations. The system defines and processes objects in a windowing environment in response to operations performed by the users of the workstations for permitting concurrent real time communication between the users. A differentiation is made between public interactive windows and private windows accessible to only one user. The private windows violate the concept of strict WYSIWIS, but are necessary to enable effective communication. Thus, objects can be manipulated by a user in windows personal to that user on his or her workstation display device and then presented to a group of users in a window which can be viewed on the workstation display device of each of the group of users.
In the environment described by Stefik et. al, there is also the problem of the management of a large number of objects. In this case there is the specific problem of how to determine which of an individual users' objects are to be made available to the other users of the system.